The present invention generally relates to innerseals of the type which seal over a container opening and which are disposed under a cap. More specifically, the present invention relates to a system for applying an innerseal to seal over a container opening in combination with a seal securable in a cap.
Seals are known which are made of a pulpboard layer and a foil layer, with a wax layer inbetween. Such "waxbond" seals are used, for example, on ketchup bottles. In such prior art seals, the seal is inserted into a cap, pulpboard side first. The cap is then tightened over the mouth of the container so that the foil side contacts against a lip of the container opening. Through a heat induction process, the foil is adhered to the lip by a heat-activatable adhesive, and the wax melts. Desirably, most of the melted wax is absorbed by the pulpboard so that the pulpboard layer and foil layer are separated or easily separatable.
A consumer who opens the container for the first time removes the cap, which retains the pulpboard layer inside, thereby separating the pulpboard layer from the foil layer. The foil layer may then be peeled from the container opening to access the container contents. The waxed pulpboard in the cap then subsequently acts as a seal when the cap is tightened after each use.
Unfortunately, conventional waxed pulpboard backing is not completely resistant to liquids. For instance, after the foil is removed, the waxed pulpboard is directly exposed to the container's contents. If the pulpboard has any defects, such as where it is incompletely waxed, liquid contents; e.g., ketchup, fruit juice, etc.; might be absorbed by the pulpboard, causing the pulpboard to degrade and weaken.
Furthermore, pulpboard seals, which generally are of beer coaster stock thickness, may shear or tear when the cap is tightened or loosened. Liquid-soaked pulpboard is especially susceptible to this.
Also, conventional pulpboard is difficult to cleanly cut with a die. This impedes manufacturing efficiency and creates undesired dust in the manufacturing environment.
Therefore, it is desirable to provide an improved layered seal having a cap backing portion and a foil portion with a wax bond inbetween wherein the cap backing portion is strong and resistant to tearing, resistant to liquids, and cleanly cuttable by a die.